Geography of Ecuador

Ecuador is one of the smaller countries in South America. Located on the
west coast and straddling the equator, Ecuador has a total area of about
280,000 square kilometers, which includes the Galápagos Islands. Roughly
the size of the state of Colorado, Ecuador encompasses a wide range of
natural formations and climates, from the desertlike southern coast to the
snowcapped peaks of the Andes Mountains to the plains of the Amazon River
Basin.

Ecuador is bounded on the west by the Pacific Ocean, on the north by
Colombia, and on the east and south by Peru. Ecuador continues to contest
the boundary with Peru, which was established by the Protocol of Peace,
Friendship, and Boundaries (Rio Protocol) of 1942 and ceded to Peru a large
portion of territory east of the Andes.

Natural Regions

Ecuador is divided into three continental regions--the Costa, Sierra, and
Oriente--and one insular region--the Galápagos Islands. The continental
regions extend the length of the country from north to south and are
separated by the Andes Mountains. The Galápagos Islands, officially called
the Archipiélago de Colón, are located 1,000 kilometers west of the
Ecuadorian coast within 1 south of the equator.

The Costa, located between the Pacific Ocean and the Andes Mountains,
consists of coastal lowlands, coastal mountains, and rolling hills that
separate river valleys. The widest part of the region stretches 150
kilometers from Cabo San Lorenzo in Manabí Province to the foothills of the
Andes Mountains. In the southern part of Guayas Province, east of the Gulf
of Guayaquil, the narrow coastal plain is only fifteen to twenty kilometers
wide. The lowlands of the Costa do not exceed 200 meters in elevation,
whereas the coastal mountains extend no higher than 1,000 meters. The
coastal mountain chain, known as the Cordillera Costañera, divides the
region into the Costa Externa, next to the coast, and the Costa Internal,
next to the Andes. The Cordillera Costañera reaches from Esmeraldas in the
north to Guayaquil in the south. North of Portoviejo in Manabí Province,
the Cordillera Costañera loses its character as a mountain chain and
becomes a series of hills and small mountains.

The Sierra consists of two major chains of the Andes mountains, known as
the Cordillera Occidental (Western Chain) and Cordillera Oriental (Eastern
Chain), and the intermontane basin or plateau between the two chains.
Several transversal mountain spurs, known as nudos, cut across the plateau.
The Nudo del Azuay, at 4,500 meters the highest of these transversal spurs,
divides the Sierra into two subregions--the area of modern volcanism to the
north and the area of ancient volcanism to the south. The former area
consists of newer, higher mountains than those in the ancient volcanism
section, which with time have eroded to lower levels.

The Sierra has at least twenty-two peaks over 4,200 meters in height. Of
the two cordilleras, the Cordillera Oriental is wider and generally higher,
with peaks averaging over 4,000 meters. The Cordillera Occidental, however,
contains the highest point in Ecuador, which is the Mount Chimborazo at
6,267 meters. The Sierra also contains the highest point on the equator,
Mount Cayambe at 5,790 meters.

The Sierra has at least thirty peaks of volcanic origin, including six
still active. These peaks, which vary in width from 80 to 130 kilometers,
are located in the area of modern volcanism known as the Avenue of the
Volcanos. The most active volcano is Mount Sangay, 5,230 meters high.
Although its last major outpouring of lava occurred in 1946, specialists
consider Mount Sangay to be in a constant state of eruption because of fires
and bubbling lava at its crater. Mount Cotopaxi, at 5,897 meters the highest
active volcano in the world, last erupted in 1877 and is now listed as
"steaming." Its crater is 800 meters in diameter. In addition to
the other damage caused by eruptions, volcanos in the Sierra have melted
snowcaps, which in turn generate massive mudslides and avalanches.
Earthquakes and tremors also are common in the region.

The intermontane plateau between the two cordilleras is divided by the
nudos into roughly 10 basins, or hoyas, that range from 2,000 to 3,000
meters in altitude. The average altitude of the plateau is 2,650 meters.

The Oriente to the east of the Cordillera Oriental consists of two
subregions: the Andean piedmont and the Eastern lowlands. The piedmont drops
from a height of 3,353 meters to the featureless lowlands, which spread out
at an altitude of 150 to 300 meters.

The Galápagos Islands consist of a chain of large, medium, and small
islands that have a combined area of roughly 8,000 square kilometers. The
largest island is Isabela Island, also known as Albemarle Island, which is
120 kilometers long with an area of 4,275 square kilometers. All of the
islands are of volcanic origin, and some have active cones. Santo Tomás,
located on Isabela Island, is the highest peak of the Galápagos at 1,490
meters. Its crater is ten kilometers in diameter.

Drainage

Almost all of the rivers in Ecuador rise in the Sierra region and flow
east toward the Amazon River or west toward the Pacific Ocean. The rivers
rise from snowmelt at the edges of the snowcapped peaks or from the abundant
precipitation that falls at higher elevations. In the Sierra region, the
streams and rivers are narrow and flow rapidly over precipitous slopes.
Rivers may slow and widen as they cross the hoyas yet become rapid again as
they flow from the heights of the Andes to the lower elevations of the other
regions. The highland rivers broaden as they enter the more level areas of
the Costa and the Oriente.

In the Costa region, the Costa Externa has mostly intermittent rivers
that are fed by constant rains from December through May and become empty
riverbeds during the dry season. The few exceptions are the longer,
perennial rivers that flow throughout the Costa Externa from the Costa
Internal and the Sierra on their way to the Pacific Ocean. The Costa
Internal, by contrast, is crossed by perennial rivers that may flood during
the rainy season, sometimes forming swamps.

The Guayas River system, which flows southward to the Gulf of Guayaquil,
constitutes the most important of the drainage systems in the Costa
Internal. The Guayas River Basin, including land drained by its tributaries,
is 40,000 square kilometers in area. The sixty-kilometer-long Guayas River
forms just north of Guayaquil out of the confluence of the Babahoyo and
Daule rivers. Briefly constricted at Guayaquil by hills, the Guayas widens
south of the city and flows through a deltaic network of small islands and
channels. At its mouth, the river forms a broad estuary with two channels
around Puná Island, the deeper of which is used for navigation.

The second major Costa river system--the Esmeraldas--rises in the Hoya de
Quito in the Sierra as the Guayllabamba River and flows westward to empty
into the Pacific Ocean near the city of Esmeraldas. The Esmeraldas River is
320 kilometers long and has a 20,000-square-kilometer drainage basin.

Major rivers in the Oriente include the Pastaza, Napo, and Putumayo. The
Pastaza is formed by the confluence of the Chambo and the Patate rivers,
both of which rise in the Sierra. The Pastaza includes the Agoyan waterfall,
which at sixty-one meters is the highest waterfall in Ecuador. The Napo
rises near Mount Cotopaxi and is the major river used for transport in the
Eastern lowlands. The Napo ranges in width from 500 to 1,800 meters. In its
upper reaches, the Napo flows rapidly until the confluence with one of its
major tributaries, the Coca River, where it slows and levels off. The
Putumayo forms part of the border with Colombia. All of these rivers flow
into the Amazon River. The Galápagos Islands have no significant rivers.
Several of the larger islands, however, have freshwater springs.

Climate

Each region has different factors that affect its climate. The Costa is
influenced primarily by proximity to warm or cool ocean currents. By
contrast, climate in the Sierra varies more as a function of altitude. The
Oriente has a fairly uniform climate that varies only slightly between the
two subregions. Climate in the Galápagos Islands is both moderated by the
ocean currents and affected by altitude. Throughout Ecuador variation in
rainfall primarily determines seasons. Temperature is determined by
altitude. With each ascent of 200 meters in altitude, temperature drops 1°
C. This phenomenon is particularly significant in the Sierra.

The Costa has a tropical climate. Temperatures for the region as a whole
remain fairly constant, ranging from 23° C in the south to 26° C in the
north. Although seasonal changes in temperature are not pronounced, the
hottest period occurs during the rainy season, especially from February to
April. Near Guayaquil, the coolest months are August and September. Rainfall
in the Costa decreases from north to south, with vegetation changing from
tropical rainforest in the north to tropical savannah to desert in the
south.

Differences in temperature and rainfall in the Costa are caused by the
Peruvian Current and periodic appearances of El Niño. The Peruvian Current,
also formerly known as the Humboldt, is a cold ocean current that flows
north along the coasts of Chile and Peru. At Cabo Blanco, where the Gulf of
Guayaquil begins, the main current veers to the west; a branch continues
northward to Cabo Pasado, in Manabí Province, where it also turns westward
to merge with the main current near the Galápagos Islands. The cold water
and air temperatures associated with the Peruvian Current inhibit rainfall
along the coast, creating dry to arid conditions. This effect is greatest
along the southern coast of Ecuador.

The El Niño occurs periodically every six or seven years. Starting in
late December, a change in atmospheric pressure shifts ocean currents so
that warm waters come closer to shore and displace the cold waters. During
this time, air and water temperatures, tides, sea levels and wave heights,
and relative humidity all are higher than usual. These conditions produce
heavy rainfall that generally lasts until May in an area that normally
experiences nothing more than a drizzle. The resulting flooding and
landslides can be devastating.

When the Peruvian Current is dominant, the amount of precipitation along
the coast varies from north to south, with levels ranging from 300
centimeters to 30 centimeters, respectively. Two rainy seasons in the
northernmost part of the coast become a single season (December through
June) not far south. Near Esmeraldas, average annual rainfall is 250
centimeters. The rainy season shortens farther south, lasting only from
January to May at Guayaquil. Very little rainfall occurs on the end of the
Santa Elena Peninsula west of Guayaquil. Arid conditions prevail on the
border with Peru south of the Gulf of Guayaquil.

Separated from the effects of ocean currents by the Cordillera Costañera,
the Costa Internal has a hot and humid climate. Temperatures can surpass 26°
C, and the vegetation and cloud cover tend to retain and augment the heat.
Rain is constant during the winter months of December through May, with the
heaviest rainfall occurring in February and March.

Temperatures in the Sierra do not vary greatly on a seasonal basis; the
hottest month averages 16° C and the coolest month, 13° C in the upper
elevations. Diurnal temperatures, however, vary dramatically, from cold
mornings to hot afternoons. The almost vertical sun and the rarified air in
the higher Sierra region allow the land to warm quickly during the day and
lose heat quickly at night. Mornings typically are bright and sunny, whereas
afternoons often are cloudy and rainy. In general, rainfall amounts are
highest on exposed locations at lower altitudes. Rain also can vary on a
local basis. Sheltered valleys normally receive 50 centimeters per year,
whereas annual rainfall is 150 centimeters in Quito
and can reach 250 centimeters on exposed slopes that catch rain-bearing
winds. On a seasonal basis, the driest months are June through September.

Climate in the Sierra is divided into levels based on altitude. The
tropical level--400 to 1,800 meters--has temperatures ranging from 20° C to
25° C and heavy precipitation. The subtropical level-- 1,800 to 2,500
meters--has temperatures from 15° C to 20° C and moderate precipitation.
The temperate level--2,500 to 3,200 meters- -has a year-round temperature in
the range of 10° C to 15° C and an annual rainfall of 100 centimeters. The
temperate level experiences rainstorms, hailstorms, and fog. Winter, or the
rainy season, lasts from January through June, and the dry season or summer
from July through December. Most rain falls in April. There also is a short
rainy period in early October caused by moisture penetrating the Sierra from
the Oriente. Quito and most other populated areas in the Sierra are located
at this temperate level. The cold level extends from the temperate zone to
4,650 meters. Here, average temperatures are 3° C to 9° C, and the
precipitation often appears in the form of rain, hail, and thick fog. Above
4,650 meters is the frozen level, where peaks are constantly capped with
snow and ice, and temperatures range from below zero to 3° C. Precipitation
frequently is in the form of snow, fog, and rain.

The Eastern lowlands in the Oriente experience an equatorial climate.
Rainfall is abundant, especially in the Andean piedmont, sometimes exceeding
500 centimeters per year. Temperatures average 25° C in the western parts
of this region. The jungle-covered plains of the Eastern lowlands register
high levels of rainfall and temperatures surpassing 28° C.

Being located on the equator, the Galápagos Islands would have an
equatorial climate were it not for the modifying effects of the Peruvian
Current. Instead, climate on the islands follows a pattern more like that of
the Sierra than the Costa. At sea level, the land is desertlike with
temperatures of 21° C. The eight summer months experience no precipitation,
whereas the winter months of January through April have some fog and
drizzle. Above sea level to an altitude of 450 meters, the islands have a
mixture of tropical, subtropical, and temperate climates. In general,
temperatures are around 17° C. There is constant fog and drizzle in the
summer and rain in the winter. The cold level above 450 meters has
temperatures below 14° C.